Suppressive Effect of α-Tocopherol Complexed with β-Cyclodextrin on the Oxidation of Methyl Linoleate

Abstract

α-Tocopherol complexed with β-cyclodextrin was prepared, and its suppressive effect on the oxidation of methyl linoleate was kinetically examined using the Weibull model. The rate constant, k, of the Weibull equation, for α-tocopherol oxidation of methyl linoleate was nearly equal to that observed with a mixture of α-tocopherol and β-cyclodextrin. Doubling the amount of α-tocopherol further reduced the k value, but the extent of the reduction was not large. All k values with the inclusion complex were lower than those without it. As the amount of free α-tocopherol only slightly affected the suppressive activity, the inclusion complexing of α-tocopherol with β-cyclodextrin contributes to lowering the k value. The suppressive effect of α-tocopherol complexed with β-cyclodextrin on methyl linoleate oxidation is due to the protection of α-tocopherol by its inclusion in β-cyclodextrin and the gradual release of α-tocopherol from the inclusion complex to the lipid phase.